Fluorescence spectra of pigmented human (age 23-97, normal and brunescent) and animal (chipmunk, 1 yr.) lenses have been obtained with laser excitation at 406.7, 413.1, 454.5 457.9, 465.8, 476.5, 488.0, 496.5, 501.7, 514.5, 520.8, 530.9, 568.2, 600.0, 610.0, 620.0, 630.0, 647.1, and 676.4 nm. All the lenses examined exhibited strong and similar fluorescence when the excitation wave-lengths are shorter than 460 nm. However, with excitation at 568.2 nm or longer the yellow pigments in chipmunk lens show dramatically different emission properties from those in the older and brunescent human lenses. The sulfhydryl concentration in the central nucleus of rat and mouse lenses falls precipitiously with age. However, in the lenses of man and water buffalo the sulfhydryl decreases at a much slower rate with age. This difference between the two groups appears to be correlated with the derivation of albuminoid: in the rodents it is chiefly gamma-crystallin which gives rise to albuminoid while in human and bovine lenses albuminoid is related to gamma-crystallin.